New project: System add-on to notify JAWS users on ESR

The deadline is indicative, but I put it at the end of this week to
highlight that the sooner translations are available, the sooner they
can ship as part of the system add-on.

The list of locales is based on telemetry data, and covers the
languages that are using an obsolete version of JAWS (screen reader)
on Firefox ESR. These users were on 52, and updating automatically to
60 (new ESR version), they found themselves without a screen reader.
The system add-on disables e10s on such systems, and warn the user
about new Firefox features being disabled to restore full
accessibility support.